Sandra Day O’Connor, who in 1981 became the first woman to serve on the U.S. Supreme Court, announced on Tuesday that she had been diagnosed with dementia, Reuters reports. “Some time ago, doctors diagnosed me with the beginning stages of dementia, probably Alzheimer’s disease," O’Connor, 88, wrote in a letter.

"While the final chapter of my life with dementia may be trying, nothing has diminished my gratitude and deep appreciation for the countless blessings of my life,” she added. After being nominated to the Supreme Court by President Ronald Reagan, O’Connor for a quarter-century occupied the bench, where she helped “break barriers for women in the legal profession,” Chief Justice John Roberts said in a statement, per Reuters.

O’Connor retired from the Supreme court in 2006 so she could focus on the well-being of her husband after he was diagnosed with Alzheimer’s disease. Because of her diagnosis, O’Connor wrote that she has decided to withdraw from public life, and will “continue living in Phoenix, Arizona, surrounded by dear friends and family.”

As SELF explained previously, Alzheimer's is a progressive neurodegenerative condition and the most common cause of dementia.

Researchers still aren’t totally sure what causes Alzheimer’s disease. But we do know that it's a condition in which a person's brain cells are damaged or destroyed, leading their cognitive functioning to progressively deteriorate through five stages, the Mayo Clinic explains.

Noticeable symptoms start to appear in the second stage and may include difficulty making decisions and mild memory issues, which then become more severe. In the third stage, mild dementia occurs, which may cause more noticeable memory lapses, like misplacing items, missing appointments, or getting lost in even familiar locations. It can also cause mood changes and make it hard for people to express themselves. From there, symptoms become even more severe and may significantly impact a person's ability to function in their relationships and job.

“How fortunate I feel to be an American and to have been presented with the remarkable opportunities available to the citizens of our country,” O'Connor added, per The Washington Post. “As a young cowgirl from the Arizona desert, I never could have imagined that one day I would become the first woman justice on the U.S. Supreme Court.”